Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like, conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent structure. The absorbent structure is typically located between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer. The absorbent structure can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the trade name HUGGIES by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body exudate, especially when the absorbent article is being worn by a newborn or other very young wearers. Insult amounts in such wearers tend to be very small. Other wearers might also produce very small insults.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators include various passive indicators such as indicator strips, printing, or other devices within each absorbent article, requiring a caregiver to pay for the wetness indicator in each absorbent article whether or not the caregiver intends to use the wetness indicator. Wetness indicators can also include alarm devices that are designed to assist parents or attendants in identifying a wet absorbent article condition early on. The devices can produce an audible, tactile, electromagnetic, or visual signal. Many of these devices rely on electronics, including conductive elements within each absorbent article that can increase the expense of the absorbent article.
In some aspects, for instance, conductive threads or foils have been placed in the absorbent articles that extend from the front of the article to the back of the article. The conductive materials serve as conductive leads for a signaling device and form an open circuit in the article that can be closed when a body fluid, such as urine, closes the circuit.
Incorporating conductive leads into absorbent articles, however, has caused various problems. For example, absorbent articles are typically mass produced on very fast moving machinery. Incorporating conductive leads into an absorbent article at conventional machine speeds has been problematic.
In addition, packaged absorbent articles are typically fed through a metal detector to ensure that there are no foreign objects contained in the package. If the conductive leads are made from or contain a metal, the metal detector can be activated registering a false positive. The incorporation of metallic materials into absorbent articles can also cause problems for those wearing the garments when attempting to pass through security gates that include metal detectors.
In view of the above, a need currently exists for a signaling system for an absorbent article that does not require conductive elements containing metal or other devices to be inserted into the interior of the article.